I havn't used either machine and am still on the fence.

Since we don't have an autoclave, and i don't want to pay for Cheyenne needle$, I have to go disposable. Now that bishop has the vice adapter for the hawk and a few companies offer disposable cart tubes I have come around to the idea.

I have gone back and forth between the thunder and flite v2.1 vice.

Nobody has ever said the Thunder isn't a great liner and color packer but it's its ability to layer soft light greys and delicate color blends that I question.
I have heard you have to adapt to the thunder and once you have you can generate soft blends. My hand speed is already very fast but I have been using a hefty amount of give on my rotary shaders, especially for smooth b&g.

On the other hand I have no doubt that you can set up a soft shader with the flite v2.1 but how does it line and pack at that same setting? I'm not going through the hassle of switching it over mid-session.

My final thoughts are that if you can't use one machine for the cartridge system it kinda defeats the purpose. Maybe there is no machine that can do it all without adjustment but I think I have sided with the Thunder.